Rose rootstock named ‘Pronne’

ABSTRACT

A new and distinct rose plant is provided which is particularly well suited for service as a rootstock for a rose scion cultivar. More specifically, when so used the scion cultivar exhibits a propensity to yield an increase in biomass and the promotion of faster bud release when compared to the results achieved when the scion cultivar is grown on its own roots or on a standard rootstock, such as ‘Natal Briar’. Both higher production rates combined with improved quality in the scion variety are facilitated. The new rose plant displays an upright growth habit with vigorous growth. Small single pink changing to near white cup-shaped blossoms are formed having five generally heart-shaped petals. Orange reproductive organs are prominently displayed at the centers of the blossoms. Medium green leaflets with finely serrated margins primarily towards the tips of leaflets and a matte upper surface are displayed.

Botanical/commercial classification: Rosa hybrida/Rose Rootstock.

Varietal denomination: cv. Pronne.

SUMMARY OF THE INVENTION

The new variety of Rosa hybrida rose rootstock was created by artificial pollination during 2006 at Overberg, The Netherlands, wherein two seedling parents were crossed which previously had been studied in the hope that they would contribute the desired characteristics. The female parent (i.e., the seed parent) was the ‘05-08’ variety (unreleased and non-patented in the United States). The male parent (i.e., the pollen parent) was the ‘236-1’ variety (unreleased and non-patented in the United States).

The parentage of the new variety can be summarized as follows: ‘05-08’×‘236-1’.

The seeds resulting from the above pollination were sown and small plants were obtained which were physically and biologically different from each other. Selective study resulted in the identification of a single plant of the new variety.

It was found that the new rose plant of the present invention:

-   -   (a) displays an upright growth habit with vigorous growth,     -   (b) forms small single pink changing to near white cup-shaped         blossoms having five generally heart-shaped petals with the         prominent display of orange reproductive organs at the center of         the blossoms,     -   (c) exhibits medium green leaflets with finely serrated margins         having a matte upper surface, and     -   (d) when used as a rootstock for a rose scion variety exhibits a         propensity to induce an increase in biomass and the promotion of         faster bud release for the scion variety.

The new variety can be readily distinguished from its ‘05-08’ and ‘236-1’ parents. More specifically, ‘05-08’ displays leaves that are more glossy on the upper surface and ‘236-1’ displays dissimilar semi-double white flowers.

The new variety provides an advantageous rootstock for use during the production of roses, including cut roses grown under greenhouse growing conditions. When the new variety is utilized as a rootstock, the scion variety commonly grows more rapidly to yield a greater biomass with thicker and longer stems within a specified period of time. Also, a yield of cut flowers commonly takes place earlier than when a standard rootstock, such as ‘Natal Briar’ (non-patented in the United States) is employed. Both higher production rates and improved quality in the scion variety are made possible. This provides the grower a significant economic advantage. The degree of increase has been found to be influenced by the scion variety in question and the cultivation conditions. Also, the new rootstock may make possible an acceptable yield at lower temperatures and the use of less artificial lighting.

A particularly advantageous increase in biomass has been observed when the scion variety is the ‘KORcut 0006’ variety (non-patented in the United States), the ‘KORsteimm’ variety (U.S. Plant Pat. No. 20,700), and the ‘KORcoluma’ variety (U.S. Plant Pat. No. 17,047). A lesser overall biomass, and lesser stem length, commonly have been found to be exhibited when such scion varieties are grown on their own roots or on a standard ‘Natal Briar’ rootstock.

Filed concurrently herewith are two additional United States Plant Patent Applications directed to other distinctive new rose rootstocks developed through the plant breeding and selection research of Applicant. These are U.S. Plant patent application Ser. No. 13/998,983 entitled Rose Rootstock Named ‘Protatu’, and U.S. Plant patent application Ser. No. 13/998,985 entitled Rose Rootstock Named ‘Protano’.

Standard DNA analysis using Simple Sequence Repeat (SSR) or microsatellites can be utilized to distinguish the new ‘Pronne’ cultivar from other rose varieties, including the ‘Protatu’ and ‘Protano’ varieties. The presence or absence of eight standard markers with scored alleles (i.e., RHB303, RHD221, RHE2A, RHI402, RHJ404, RHM405, RHO517, and RHP519) can be utilized and were evaluated with respect to the ‘Pronne’, ‘Protatu’, and ‘Protano’ varieties as reported in the TABLE 1 that follows. This determination was carried out at Stichting Nederlandse Algemene Kwaliteitsdienst Tuinbouw (Netherlands Inspection Service for Horticulture), better known as Naktuinbouw. DNA from leaf samples of each cultivar was extracted using the standard Naktuinbouw CTAB DNA isolation protocol. The generated DNA fragments (alleles) were separated by gel electrophoresis. SSR DNA profiles were generated for each variety. The generated DNA fragments (alleles) were separated by gel electrophoresis. The alleles were scored present or absent and are reported hereafter.

TABLE 1 Marker RHB303 RHD221 RHE2A RHI402 RHJ404 RHM405 RHO517 RHP519 ‘Pronne’ H F B,D A,D D C,D C,D C ‘Protatu’ H F D A,E D B,D C,D C,F ‘Protano’ G,H F D A,B D C,D C,D C,F The difference between ‘Pronne’ and ‘Protatu’ is 6 of the 53 alleles. The difference between ‘Pronne’ and ‘Protano’ is 5 of the 53 alleles. The difference between ‘Protatu’ and ‘Protano’ is 5 of the 53 alleles. See G. D. Esselink, M. J. M. Smulders, and B. Voeman, “Identification of cut rose (Rosa hybrida) and rootstock varieties using robust sequence tagged microstallite site markers,” Theor Appl Genet, No. 106, Pages 277 to 286 (2003).

The new variety of the present invention has been found to undergo asexual propagation beginning in 2008 at Overberg, The Netherlands, by the rooting of stem cuttings. Asexual propagation by the above-mentioned technique has shown that the characteristics of the new variety are stable and are strictly transmissible by such asexual propagation from one generation to another. Accordingly, the new variety undergoes asexual propagation in a true-to-type manner.

The new cultivar initially was designated ‘08-41’ and has been named ‘Pronne’. At times, “PRO-4” has been associated with this cultivar.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying photographs show as nearly true as it is reasonably possible to make the same, in color illustrations of this character, typical specimens of the plant parts of the new variety. The rose plants of the new variety were approximately five years of age and were observed during June while growing outdoors on their own roots in sandy soil at Overberg, The Netherlands.

FIG. 1 illustrates typical foliage and buds and flowers of the new variety in various stages of development. The fading of the initial pink blossom coloration to near white upon maturity is depicted.

FIG. 2 illustrates a close view of a typical recently-opened pink flower of the new cultivar wherein a profusion of orange reproductive parts is displayed at the center of the blossom. The presence of darker pink/light red unopened buds also is depicted as is the finely serrated margins of the foliage. Such serrations commonly are concentrated towards the apex of the leaflets. Dimensions in centimeters are included for comparative purposes.

DETAILED BOTANICAL DESCRIPTION

The chart used in the identification of the colors is that of The Royal Horticultural Society (R.H.S. Colour Chart—1995 edition or equivalent). The description is based on the observation of five-year-old plants during June while growing outside in sandy soil at Overberg, The Netherlands.

-   Class: Most closely resembles Rosa multiflora. -   Plant:     -   -   Growth habit.—Substantially upright.         -   Height.—Commonly approximately 1.75 m on average.         -   Width.—Commonly approximately 60 cm on average.         -   Roots.—Exhibit no propensity to sucker when used as a             rootstock, display good compatibility with scions, provide             good anchorage, and impart good vigor when used as a             rootstock. -   Branches:     -   -   Stems.—Color: when young commonly near Red Group 53A on the             upper side and near Yellow-Green Group 144B on the             underside, and when mature commonly near Yellow-Green Group             144B and without anthocyanin coloration. Diameter: commonly             approximately 7 mm on average. Texture: generally smooth.         -   Internode length.—Commonly approximately 4.8 cm on average.             Such internode length renders the plant well suited for             stenting as indicated hereafter.         -   Thorns.—Commonly few, and when present commonly near Red             Group 46A in coloration, and approximately 4 mm in length. -   Foliage:     -   -   Petioles.—Length: approximately 12 mm on average. Diameter             approximately 1 mm on average. Texture: commonly smooth and             without small thorns. Color: commonly near Red Group 46A on             the upper side and near Yellow-Green Group 144C on the             underside.         -   Rachis.—Color: commonly near Yellow-Green Group 146A.         -   Leaves.—Length: commonly approximately 12 cm on average.             Width: commonly approximately 8 cm on average.         -   Leaflets.—Number: commonly 7 and 9. Shape: generally             elliptical with a somewhat acuminate tip and an obtuse base.             Size: the terminal leaflets commonly are approximately 50 mm             in length on average, and approximately 27 mm in width on             average. Serration: small and fine and commonly             approximately 1 mm in size. Such serration tends to be             concentrated at approximately 50 percent of the margin of             each leaflet and is located at the tip. Texture: with a             matte upper surface. Color: commonly near Yellow-Green Group             146A on both surfaces and commonly without anthocyanin             coloration. -   Inflorescence:     -   -   Number of flowers.—Commonly borne in clusters.         -   Type.—Single.         -   Time of flowering.—Commonly commences in late June.         -   Peduncle.—Length: commonly approximately 2.5 cm on average.             Diameter: commonly approximately 1 mm on average. Color:             commonly near Red Group 46A on the upper side and without             anthocyanin coloration on the underside. Texture: commonly             slightly glandular.         -   Pedicel.—Color commonly near Red Group 46A on the upper side             and without anthocyanin coloration on the underside.         -   Buds.—Shape: substantially conical. Color commonly near             Greyed-Purple Group 187B when sepals are closed, and near             Red-Purple Group 65A when sepals are open.         -   Flower.—Shape: cup-shaped. Diameter small, approximately 2.5             cm on average. Depth: commonly approximately 5 mm when open.             Number: commonly approximately 30 to 50 flowers per             inflorescence on average. Color (in the course of opening):             Upper surface: near White Group NN155D suffused with near             Red Group 55D. Under surface: near White Group 155A suffused             with near Red Group 55D. Color (mature open flower): Upper             side: near White Group 155A. Under side: near White Group             155A. Fragrance: none detected. Petal number: 5 under normal             growing conditions. Petal shape: generally heart-shaped.             Petal arrangement: somewhat imbricated, and without             petaloids. Stamen number: approximately 80 on average.             Filaments: near Yellow Group 2B in coloration. Anthers:             regularly arranged around the styles, and commonly             Green-Yellow Group 1B in coloration. Pollen: present, and             near orange in coloration. Pistils: connated and fused, and             commonly number approximately 10 on average. Stigmas:             commonly near Yellow-Green Group 154A in coloration. Styles:             generally orange in coloration. Lastingness: commonly             approximately 15 days on the plant and influenced by             environmental conditions.         -   Sepals.—Color commonly with anthocyanin coloration. Length:             approximately 1 to 1.5 cm on average. Width: commonly             approximately 2 to 3 mm on average. Texture: with numerous             glands which impart roughness.         -   Hips.—Shape: generally ovate. Size: commonly approximately 1             cm in length on average and approximately 8 mm in diameter             on average. -   Development:     -   -   Vegetation.—Very strong.         -   Blooming.—Commonly commences and ends in June.         -   Hardiness.—Has well withstood −15° C. at Overberg, The             Netherlands.         -   Tolerance to diseases.—Good, with no particular             susceptibility to common diseases having been encountered             during observations to date.         -   Asexual reproduction.—Cuttings readily undergo rooting.         -   Use as understock.—Stenting can be utilized when the new             variety serves as a rose understock for a scion rose             variety. In this instance, quick overall propagation can be             achieved by grafting the scion variety on an unrooted             cutting of the new variety. A resulting complete plant can             be formed thereafter in approximately three weeks. This             technique was developed by Peter A. van de Pol of Wageningen             Agricultural University (The Netherlands). The word             “stenting” is a contraction of the Dutch words “Stekken”             (rooting of a cutting) and “Enten” (grafting). The technique             and word were first published in 1979 in the Dutch Vakblad             voor de Bloemisterij, No. 26, Pages 40 to 41, and in English             in 1982, “Stenting of roses; A method for quick propagation             by simultaneously cutting and grafting,” Scientia             Horticulture, No. 17, Pages 187 to 196.

The new ‘Pronne’ variety has not been observed under all possible environmental conditions to date. Accordingly, it is possible that the phenotypic expression may vary somewhat with changes in light intensity and duration, cultural practices, and other environmental conditions. 

I claim:
 1. A new and distinct rose plant characterized by the following characteristics: (a) displays an upright growth habit with vigorous growth, (b) forms small single pink changing to near white cup-shaped blossoms having five generally heart-shaped petals with the prominent display of orange reproductive organs at the center of the blossoms, (c) exhibits medium green leaflets with finely serrated margins having a matte upper surface, and (d) when used as a rootstock for a cut rose scion variety exhibits a propensity to yield an increase in biomass and the promotion of faster bud release for the scion variety; substantially as shown and described. 